Why am I getting an OpenCL driver error with BlendLuxCore when I'm rendering using CPU only?
So, I took a wild guess and installed the OpenCL running environment for my intel CPU only from this site: https://software.intel.com/content/www/us/en/develop/articles/opencl-drivers.html#latest_linux_SDK_release
After I did that, LuxRender works.
If somebody wants to add an explanation about why I needed to do this in the first place (I am partially confused because the LuxRender web site makes no reference to this being a dependency you need to set up before installing), that would be cool. But, my problem is solved, and I'm going to tentatively assume that LuxRender is using OpenCL as a sort of backend to abstract away hardware details like whether you are on a CPU or a GPU and what types.